Several figures have been announced from time to time, no two of them
in agreement with each other; but all of these, it is to be observed,
were obtained by more or less approximate methods. In 1913 the United
States Geological Survey, in connection with its topographic surveys
of the Mount Rainier National Park, was able to make a new series of
measurements by triangulation methods at close range. These give the
peak an elevation of 14,408 feet, thus placing it near the top of the
list of high summits of the United States. This last figure, it should
be added, is not likely to be in error by more than a foot or two and
may with some confidence be regarded as final. Greater exactness of
determination is scarcely practicable in the case of Mount Rainier, as
its highest summit consists actually of a mound of snow the height of
which naturally varies somewhat with the seasons and from year to
year.
This crowning snow mound, which was once supposed to be the highest
point in the United States, still bears the proud name of Columbia
Crest. It is essentially a huge snowdrift or snow dune, heaped up by
the westerly winds. Driving furiously up through the great breach in
the west flank of the mountain, between Peak Success and Liberty Cap,
they eddy lightly as they shoot over the summit and there deposit
their load of snow.
The drift is situated at the point where the rims of the two summit
craters touch, and represents the only permanent snow mass on these
rims, for some of the internal heat of the volcano still remains and
suffices to keep these rock-crowned curving ridges bare of snow the
better part of the year. It is intense enough, even, to produce
numerous steam jets along the inner face of the rim of the east
crater, which appears to be the most recently formed of the two. The
center of this depression, however, is filled with snow, so that it
has the appearance of a shallow, white-floored bowl some 1,200 feet in
diameter. Great caverns are melted out by the steam jets under the
edges of the snow mass, and these caverns afford shelters which,
though uninviting, are not to be despised. They have proved a
blessing to more than one party that has found itself compelled to
remain overnight on the summit, saving them from death in the icy
gales.
That Mount Rainier should still retain so much of its internal heat is
not surprising in view of the recency of its eruptions. It is known to
have been active at intervals during the last century, and actual
record exists of slight eruptions in 1843, 1854, 1858, and 1870.
Indian legends mention a great cataclysmal outburst at an earlier
period.
At present the volcano may be regarded as dormant and no apprehension
need be felt as to the possibility of an early renewal of its
activity. The steam jets in the summit crater, it is true, as well as
the hot springs at the mountain's foot (Longmire Springs), attest the
continued presence of subterranean fires, but they are only feeble
evidences as compared with the geysers, the steam jets, and the hot
springs of the Yellowstone National Park. Yet that region is not
considered any less safe to visit because of the presence of these
thermal phenomena.
In spite of Mount Rainier's continued activity until within the memory
of man its sides appear to have been snow clad for a considerable
length of time. Indeed, so intense and so long-continued has been the
eroding action of the ice that the cone is now deeply ice-scarred and
furrowed. Most of its outer layers, in fact, appear already to have
been stripped away. Here and there portions of them remain standing on
the mountain's flanks in the form of sharp-crested crags and ridges,
and from these one may roughly surmise the original dimensions of the
cone. Mere details in the volcano's sculpture, these residual masses
are, some of them, so tall that, were they standing among ordinary
mountains, they would be reckoned as great peaks. Particularly
noteworthy is Little Tahoma, a sharp, triangular tooth on the east
flank, that rises to an elevation of 11,117 feet. In its steep,
ice-carved walls one may trace ascending volcanic strata aggregating
2,000 feet in thickness that point upward to the place of their
origin, the former summit of the mountain, which rose almost half a
mile higher than the present top.
Nor is the great crater rim left by the explosion that carried off the
original summit preserved in its entirety. Peak Success and Liberty
Cap are the only two promontories that give trustworthy indication of
its former height and strength. Probably they represent the more
massive portions on the southwest and northwest sides, respectively,
while the weaker portions to the east and south have long since
crumbled away under the heavy ice cascades that have been overriding
them for ages. Only a few small rocky points remain upon which the
snows split in their descent. The most prominent, as well as the most
interesting, is the one on the southeast side, popularly known as
Gibraltar Rock. Really a narrow, wedge-shaped mass, it appears in
profile like a massive, square-cut promontory. The trail to the summit
of the mountain passes along its overhanging south face and then
ascends by a precipitous chute between ice and rock. It is this part
of the ascent that is reputed as the most precarious and hazardous.
From the rim points downward the ice cover of the cone divides into a
number of distinct stream-like tongues or glaciers, each sunk in a
great hollow pathway of its own. Between these ice-worn trenches the
uneroded portions of the cone stand out in high relief, forming as a
rule huge triangular "wedges," heading at the sharp rim points and
spreading thence downward to the mountain's base. There they assume
the aspect of more gently sloping, grassy table-lands, the charming
alpine meadows of which Paradise Park and Spray Park are the most
famous. Separating these upland parks are the profound ice-cut
canyons which, beyond the glacier ends, widen out into densely
forested valleys, each containing a swift-flowing river. No less than
a dozen of these ice-fed torrents radiate from the volcano in all
directions, while numerous lesser streams course from the snow fields
between the glaciers.
Thus the cone of Mount Rainier is seen to be dissected from its summit
to its foot. Sculptured by its own glacier mantle, its slopes have
become diversified with a fretwork of ridges, peaks, and canyons.
The first ice one meets on approaching the mountain from Longmire
Springs lies in the upper end of the Nisqually Valley. The wagon road,
which up to this point follows the west side of the valley, winding in
loops and curves along the heavily wooded mountain flank, here
ventures out upon the rough bowlder bed of the Nisqually River and
crosses the foaming torrent on a picturesque wooden bridge. A scant
thousand feet above this structure, blocking the valley to a height of
some 400 feet, looms a huge shapeless pile of what seems at first
sight only rock débris, gray and chocolate in color. It is the
dirt-stained end of one of the largest glaciers--the Nisqually. From a
yawning cave in its front issues the Nisqually stream, a river full
fledged from the start.
The altitude here, it should be noted, is a trifle under 4,000 feet
(elevation of bridge is 3,960 feet); hence the ice in view lies more
than 10,000 feet below the summit of the mountain, the place of its
origin. And in this statement is strikingly summed up the whole nature
and economy of a glacier such as the Nisqually.
A glacier is not a mere stationary blanket of snow and ice clinging
inert to the mountain flank. It is a slowly moving streamlike body
that descends by virtue of its own weight. The upper parts are
continually being replenished by fresh snowfalls, which at those high
altitudes do not entirely melt away in summer; while the lower end,
projecting as it does below the snow line, loses annually more by
melting than it receives by precipitation, and is maintained only by
the continued accession of masses from above. The rate at which the
ice advances has been determined by Prof. J. N. Le Conte, of the
University of California. In 1903 he placed a row of stakes across the
glacier, and with the aid of surveying instruments obtained accurate
measurements of the distances through which they moved from day to
day. He found that in summer, when the movement is greatest, it
averages 16 inches per day. This figure, however, applies only to the
central portion of the glacier--the main current, so to speak--for the
margins necessarily move more slowly, being retarded by friction
against the channel sides.
The snout of the Nisqually Glacier, accordingly, is really composed of
slowly advancing ice, but so rapid is the melting at this low altitude
that it effectually counterbalances the advance, and thus the ice
front remains essentially stationary and apparently fixed in place.
Actually, it is subject to slight back and forward movements,
amounting to a foot or more per day; for, as one may readily imagine,
fluctuations in snowfall and in temperature, above or below the
normal, are ever likely to throw the balance one way or another.
A glacier may also make periodic advances or retreats on a larger
scale in obedience to climatic changes extending over many years. Thus
all the glaciers on Mount Rainier, as well as many in other parts of
the world, are at present, and have been for some time, steadily
retreating as the result of milder climate or of a lessening in snow
supply. Only so recently as 1885 the Nisqually Glacier reached down to
the place now occupied by the bridge, and it is safe to say that at
that time no engineer would have had the daring to plan the road as it
is now laid. In the last 25 years, however, the Nisqually Glacier has
retreated fully 1,000 feet.
Evidences of similar wholesale recession are to be observed at the
ends of the other glaciers of Mount Rainier, but the measure of their
retreat is not recorded with the precision that was possible in the
case of the Nisqually Glacier. Eyewitnesses still live at Longmire
Springs who can testify to the former extension of the Nisqually
Glacier down to the site of the wagon bridge.
As one continues the ascent by the wagon road a partial view of the
glacier's lower course is obtained, and there is gained some idea of
its stream-like character. More satisfying are the views from Paradise
Park. Here several miles of the ice stream (its total length is nearly
5 miles) lie stretched out at one's feet, while looking up toward the
mountain one beholds the tributary ice fields and ice streams,
pouring, as it were, from above, from right and left, rent by
innumerable crevasses and resembling foaming cascades suddenly
crystallized in place. The turmoil of these upper branches may be too
confusing to be studied with profit, but the more placid lower course
presents a favorable field for observation, and a readily accessible
one at that.
A veritable frozen river it seems, flowing between smooth, parallel
banks, half a mile apart. Its surface, in contrast to the glistening
ice cascades above, has the prevailingly somber tint of old ice,
relieved here and there by bright patches of last winter's snow. These
lie for the most part in gaping fissures or crevasses that run athwart
the glacier at short intervals and divide its body into narrow slices.
In the upper course, where the glacier overrides obstacles in its bed,
the crevasses are particularly numerous and irregularly spaced,
sometimes occurring in two sets intersecting at right angles, and
producing square-cut prisms. Farther down the ice stream's current is
more sluggish and the crevasses heal up by degrees, providing a united
surface, over which one may travel freely.
Gradually, also, the glacier covers itself with débris. Angular rock
fragments, large and small, and quantities of dust, derived from the
rock walls bordering the ice stream higher up, litter its surface and
hide the color of the ice. At first only a narrow ridge of such
material--a moraine, as it is called--accompanies the ice river on
each side, resembling a sharp-crested embankment built by human hands
to restrain its floods; but toward the lower end of the glacier, as
the ice wastes away, the débris contained in it is released in masses,
and forms brown marginal bands, fringing the moraines. In fact, from
here on down it becomes difficult to tell where the ice of the glacier
ends at the sides and where the moraines begin.
The lower part of the glacier also possesses a peculiar feature in the
form of a débris ridge about midway on its back--a medial moraine.
Most of the way it stretches like a slender, dark ribbon, gradually
narrowing upstream. One may trace it with the eye up to its point of
origin, the junction of the two main branches of the glacier, at the
foot of a sharp rock spur on the mountain's flank.
In the last mile of the Nisqually's course, this medial moraine
develops from a mere dirt band to a conspicuous embankment, projecting
40 feet above the ice. Not the entire body of the ridge, however, is
made up of rock débris. The feature owes its elevation chiefly to the
protective influence of the débris layer on its surface, which is
thick enough to shield the ice beneath from the hot rays of the sun,
and greatly retards melting, while the adjoining unprotected ice
surfaces are rapidly reduced.
A short distance above the glacier's terminus the medial moraine and
the ever-broadening marginal bands come together. No more clear ice
remains exposed, irregular mounds and ridges of débris cover the
entire surface of the glacier, and the moraine-smothered mass assumes
the peculiar inchoate appearance that is so striking upon first view.
In utter contrast with the glacier's dying lower end are the bright
snow fields on the summit in which it commences its career. Hard by
the rock rim of the east summit crater the snows begin, enwrapping in
an even, immaculate layer the smooth sides of the cinder cone. Only a
few feet deep at first, they thicken downward by degrees, until, a
thousand feet below the crater, they possess sufficient depth and
weight to acquire movement. Occasional angular crevasses here
interrupt the slope and force the summit-bound traveler to make
wearying detours.
Looking down into a gash of this sort one beholds nothing but clean
snow, piled in many layers. Only a faint blue tinges the crevasse
walls, darkening but slowly with the depth, in contrast to the intense
indigo hue characteristic of the partings in the lower course of the
glacier. There the material is a dense ice, more or less crystalline
in texture; here it is scarcely more than snow, but slightly compacted
and loosely granular--what is generally designated by the Swiss term
"névé."
For several thousand feet down, as far as the 10,000-foot level, in
fact, does the snow retain this granular consistency. One reason for
the slowness with which it compacts is found in the low temperatures
that prevail at high altitudes and preclude any considerable melting.
The air itself seldom rises above the freezing point, even in the
middle of the day, and as a consequence the snow never becomes soft
and mushy, as it does at lower levels.
When snow assumes the mushy, "wet-sugar" state, it is melting
internally as well as at its outer surface, owing both to the water
that soaks into it and to the warming of the air inclosed within its
innumerable tiny pores (which tiny air spaces, by the way, give the
snow its brilliant whiteness). Snow in this condition has, paradoxical
though it may sound, a temperature a few tenths of a degree higher
than the melting point--a fact recently established by delicate
temperature measurements made on European glaciers. It is this
singular fact, no doubt, that explains how so many minute organisms
are able to flourish and propagate in summer on the lower portions of
many glaciers. It may be of interest to digress here briefly in order
to speak of these little known though common forms of life.
Several species of insects are among the regular inhabitants of
glaciers. Most of them belong to a very low order--the Springtails, or
_Thysanura_--and are so minute that in spite of their dark color they
escape the attention of most passers-by. If one looks closely,
however, they may readily be observed hopping about like miniature
fleas or wriggling deftly into the cavities of the snow. It seems to
incommode them but little if in their acrobatic jumps they
occasionally alight in a puddle or in a rill, for they are thickly
clad with furry scales that prevent them from getting wet--just as a
duck is kept dry by its greasy feathers.
Especially plentiful on the lower parts of the Rainier glaciers, and
more readily recognized, are slender dark-brown worms of the genus
_Mesenchytraeus_, about 1 inch in length. Millions and millions of
them may be seen on favorable days in July and August writhing on the
surface of the ice, evidently breeding there and feeding on organic
matter blown upon the glacier in the form of dust. So essential to
their existence is the chill of the ice that they enter several
inches, and sometimes many feet below the surface on days when the sun
is particularly hot, reappearing late in the afternoon.
Mention also deserves to be made of that microscopic plant
_Protococcus nivalis_, which is responsible for the mysterious pink or
light, rose-colored patches so often met with on glaciers--the "red
snow" of a former superstition. Each patch represents a colony or
culture comprising billions of individuals. It is probable that they
represent but a small fraction of the total microflora thriving on
the snow, the other species remaining invisible for lack of a
conspicuous color.
To return to the frigid upper névés, it is not to be supposed that
they suffer no loss whatever by melting. The heat radiated directly to
them by the sun is alone capable of doing considerable damage, even
while the air remains below the freezing point. At these high
altitudes the sun heat is astonishingly intense, as more than one
uninitiated mountain climber has learned to his sorrow by neglecting
to take the customary precaution of blacking his face before making
the ascent. In a few hours the skin is literally scorched and begins
to blister painfully.
At the foot of the mountain the sun heat is relatively feeble, for
much of it is absorbed by the dust and vapor in the lower layers of
the atmosphere, but on the summit, which projects 2 miles higher, the
air is thin and pure, and lets the rays pass through but little
diminished in strength.
The manner in which the sun affects the snow is peculiar and
distinctive. Instead of reducing the surface evenly, it melts out many
close-set cups and hollows, a foot or more in diameter and separated
by sharp spires and crests. No water is visible anywhere, either in
rills or in pools, evaporation keeping pace with the reduction. If the
sun's action is permitted to continue uninterrupted for many days, as
may happen in a hot, dry summer, these snow cups deepen by degrees,
until at length they assume the aspect of gigantic bee cells, several
feet in depth. Snow fields thus honeycombed may be met with on the
slopes above Gibraltar Rock. They are wearisome to traverse, for the
ridges and spines are fairly resistant, so that one must laboriously
clamber over them. Most exasperating, however, is the going after a
snowstorm has filled the honeycombs. Then the traveler, waist deep in
mealy snow, is left to flounder haphazard through a hidden labyrinth.
Of interest in this connection is the great snow cliff immediately
west of Gibraltar Rock. Viewed from the foot of that promontory, the
sky line of the snow castle fairly bristles with honeycomb spines;
while below, in the face of the snow cliff, dark, wavy lines, roughly
parallel to the upper surface, repeat its pattern in subdued form.
They represent the honeycombs of previous seasons, now buried under
many feet of snow, but still traceable by the dust that was imprisoned
with them.
The snow cliff west of Gibraltar Rock is of interest also for other
reasons. It is the end of a great snow cascade that descends from the
rim of the old crater. Several such cascades may be seen on the south
side of the mountain, separated by craggy remnants of the crater rim.
Above them the summit névés stretch in continuous fields, but from the
rim on down, the volcano's slopes are too precipitous to permit a
gradual descent, and the névés break into wild cascades and falls.
Fully two to three thousand feet they tumble, assembling again in
compact, sluggish ice fields on the gentler slopes below.
Of the three cascades that feed the Nisqually Glacier only the central
one, it is to be observed, forms a continuous connection between the
summit névés and the lower ice fields. The two others, viz. the one
next to Gibraltar and the westernmost of the three, terminate in
vertical cliffs, over great precipices of rock. From them snow masses
detach at intervals and produce thundering avalanches that bound far
out over the inclined ice fields below. Especially frequent are the
falls from the cliff near Gibraltar. They occur hourly at certain
times, but as a rule at periods of one or more days.
From the westernmost cascade avalanches are small and rare. Indeed, as
one watches them take place at long intervals throughout a summer one
can not but begin to doubt whether they are in themselves really
sufficient to feed and maintain so extensive an ice field as lies
stretched out under them. Surely much more snow must annually melt
away from the broad surface of that field, exposed as it lies to the
midday sun, than the insignificant avalanches can replace. Were they
its only source of supply, the ice field, one feels confident, would
soon cease to exist.
The fact is that the ice field in question is not dependent for its
support on the avalanches from above. It may receive some
contributions to its volume through them, but in reality it is an
independent ice body, nourished chiefly by direct snow precipitation
from the clouds. And this is true, in large measure, of all the ice
fields lying under the ice cascades. The Nisqually Glacier,
accordingly, is not to be regarded as composed merely of the cascading
névés, reunited and cemented together, but as taking a fresh start at
these lower levels. Improbable though this may seem at first, it is
nevertheless a fact that is readily explained.
The winter snows on Mount Rainier are heaviest in the vicinity of its
base; indeed, the snowfall at those low levels is several times
greater than that on the summit. This in itself may seem anomalous. So
accustomed is one to think that the snowfall on high mountains
increases with the altitude that it seems strange to find a case in
which the opposite is true. Yet Mount Rainier stands by no means alone
in this regard. The Sierra Nevada and the Andes, the Himalayas and the
Alps, all show closely analogous conditions.
In each of these lofty mountain regions the precipitation is known to
be heaviest at moderate altitudes, while higher up it decreases
markedly. The reason is that the storm clouds--the clouds that carry
most of the rain and snow--hang in a zone of only moderate elevation,
while higher up the atmosphere contains but little moisture and seldom
forms clouds of any great density.
In the Rainier region the height of the storm clouds is in large
measure regulated by the relief of the Cascade Range; for it is really
this cooling mountain barrier that compels the moisture-laden winds
from the Pacific Ocean to condense and to discharge. It follows that
the storm clouds are seldom much elevated above the sky line of the
Cascade Mountains; they cling, so to speak, to its crest and ridges,
while the cone of Mount Rainier towers high above them into serener
skies. Many a day may one look down from the summit, or even from a
halfway point, such as Camp Muir (10,062 feet), upon the upper surface
of the clouds. Like a layer of fleecy cotton they appear, smothering
the lower mountains and enveloping the volcano's base.
Clouds, it is true, are frequently seen gathering about the mountain's
crown, usually in the form of a circular cap or hood, precursor of a
general storm, but such clouds yield but very little snow.